Heat index values remained elevated across the Midwest on Wednesday, with combined heat and humidity creating temperatures that felt like 110 degrees Fahrenheit in Chicago and Minneapolis.

High heat index values mean hot and wet conditions, which make it hard for the human body to cool off by sweating, as humidity slows evaporation of sweat from the skin. At heat index values nearing 120 F, prolonged exposure means significant danger of heat exhaustion and even heat stroke, according to the National Oceanic and Atmospheric Administration.

The National Weather Service said a high-pressure dome is creating extreme heat through the Plains and the Midwest into the South. From Minneapolis to New Orleans, roughly 130 million people in 22 states are under heat alerts that are warning against extended time outdoors.

Daily highs in the Midwest were forecast by the weather service to reach up to 20 F above average, with temperatures into the upper 90s and low 100s, likely breaking numerous daily and potentially monthly records.

The heat wave is expected to continue through the end of the week, when a cold front moving south will bring relief to parts of the Midwest. The South is expected to stay hot through the weekend.

In the Great Lakes and the Ohio Valley, 11 million people are at risk for severe storms Wednesday. High winds are likely with a chance of hail and a low chance of tornadoes. The severe storm risk is forecast to continue into Thursday.

Meanwhile, the National Hurricane Center is monitoring Tropical Storm Franklin, which made landfall on the Dominican Republic coast Wednesday morning. The storm is forecast to travel over the Dominican Republic, Haiti and Puerto Rico, bringing heavy winds and precipitation up to 15 inches into Thursday.

Flash food risk continues from west Texas into the Southwest following Tropical Depression Harold, which made landfall Tuesday morning on Padre Island in Texas.

The severe storm risk in the Great Lakes and Ohio Valley also extended into the Northern Plains. Wind gusts over 60 mph, lightning and precipitation were likely in cities such as Detroit, Cleveland and Pittsburgh, as well as possible hail and isolated tornadoes.

Tropical Storm Franklin is forecast to reach the Atlantic ocean on Thursday and will likely strengthen into a hurricane near Bermuda over the weekend. Dangerous surf and rip currents are possible on the U.S. East Coast early next week.